Question

A rectangular field 240m long has an area 36000m². Find the cost of fencing the field at Rs.2.50per m.

Answer 1

Let the breadth of the rectangle = xm
The area of a rectangle with length l and breadth b = A = l x b
∴ The area of a rectangle with length 240m and breadth xm = A = 240x
⇒ 240x = 36000

⇒ x = `(36000)/(240)`
= 150m
Now, the perimeter of a rectangle with length l and breadth b = P = 2(l + b)
∴ The perimeter of a rectangle with length 240 and breadth 150 is
P = 2(240 + 150)
= 2(390)
= 780
The cost of fencing 1m = Rs.2.50
⇒ The cost of fencing 780m
= Rs.2.50 x 780
= Rs.1950.